From 309e5c6db1c7af0da9b75b14aeff16885264122d Mon Sep 17 00:00:00 2001
From: Adam Scarr <adam@vektah.net>
Date: Thu, 3 May 2018 18:49:15 +1000
Subject: [PATCH] Automatically add a _ suffix to reserved words

---
 codegen/input_test.go   | 73 +++++++++++++++++++++++++++++++++++++++++
 codegen/object.go       |  9 ++---
 codegen/object_build.go | 44 +++++++++++++++++++++++--
 3 files changed, 119 insertions(+), 7 deletions(-)

diff --git a/codegen/input_test.go b/codegen/input_test.go
index f75d7250eb8..c4191fd7952 100644
--- a/codegen/input_test.go
+++ b/codegen/input_test.go
@@ -90,3 +90,76 @@ func TestComplexInputTypes(t *testing.T) {
 
 	require.NoError(t, err)
 }
+
+func TestKeywordInputFields(t *testing.T) {
+	err := generate("input_keywords_fields", `
+		input Object {
+			break:       String!
+			default:     String!
+			func:        String!
+			interface:   String!
+			select:      String!
+			case:        String!
+			defer:       String!
+			go:          String!
+			map:         String!
+			struct:      String!
+			chan:        String!
+			else:        String!
+			goto:        String!
+			package:     String!
+			switch:      String!
+			const:       String!
+			fallthrough: String!
+			if:          String!
+			range:       String!
+			type:        String!
+			continue:    String!
+			for:         String!
+			import:      String!
+			return:      String!
+			var:         String!
+		}
+		type Query {
+			test(input: Object): Boolean!
+		}
+	`)
+
+	require.NoError(t, err)
+}
+
+func TestInputKeywordArgs(t *testing.T) {
+	err := generate("input_keyword_args", `
+		type Query {
+			test(
+				break:       String!,
+				default:     String!,
+				func:        String!,
+				interface:   String!,
+				select:      String!,
+				case:        String!,
+				defer:       String!,
+				go:          String!,
+				map:         String!,
+				struct:      String!,
+				chan:        String!,
+				else:        String!,
+				goto:        String!,
+				package:     String!,
+				switch:      String!,
+				const:       String!,
+				fallthrough: String!,
+				if:          String!,
+				range:       String!,
+				type:        String!,
+				continue:    String!,
+				for:         String!,
+				import:      String!,
+				return:      String!,
+				var:         String!,
+			): Boolean!
+		}
+	`)
+
+	require.NoError(t, err)
+}
diff --git a/codegen/object.go b/codegen/object.go
index f1aafbaba0c..06291517817 100644
--- a/codegen/object.go
+++ b/codegen/object.go
@@ -34,9 +34,10 @@ type Field struct {
 type FieldArgument struct {
 	*Type
 
-	GQLName string      // The name of the argument in graphql
-	Object  *Object     // A link back to the parent object
-	Default interface{} // The default value
+	GQLName   string      // The name of the argument in graphql
+	GoVarName string      // The name of the var in go
+	Object    *Object     // A link back to the parent object
+	Default   interface{} // The default value
 }
 
 type Objects []*Object
@@ -67,7 +68,7 @@ func (f *Field) ResolverDeclaration() string {
 		res += fmt.Sprintf(", obj *%s", f.Object.FullName())
 	}
 	for _, arg := range f.Args {
-		res += fmt.Sprintf(", %s %s", arg.GQLName, arg.Signature())
+		res += fmt.Sprintf(", %s %s", arg.GoVarName, arg.Signature())
 	}
 
 	result := f.Signature()
diff --git a/codegen/object_build.go b/codegen/object_build.go
index 3b9e092dc71..20fd867f7d9 100644
--- a/codegen/object_build.go
+++ b/codegen/object_build.go
@@ -42,6 +42,43 @@ func (cfg *Config) buildObjects(types NamedTypes, prog *loader.Program, imports
 	return objects, nil
 }
 
+var keywords = []string{
+	"break",
+	"default",
+	"func",
+	"interface",
+	"select",
+	"case",
+	"defer",
+	"go",
+	"map",
+	"struct",
+	"chan",
+	"else",
+	"goto",
+	"package",
+	"switch",
+	"const",
+	"fallthrough",
+	"if",
+	"range",
+	"type",
+	"continue",
+	"for",
+	"import",
+	"return",
+	"var",
+}
+
+func sanitizeGoName(name string) string {
+	for _, k := range keywords {
+		if name == k {
+			return name + "_"
+		}
+	}
+	return name
+}
+
 func (cfg *Config) buildObject(types NamedTypes, typ *schema.Object) (*Object, error) {
 	obj := &Object{NamedType: types[typ.TypeName()]}
 
@@ -53,9 +90,10 @@ func (cfg *Config) buildObject(types NamedTypes, typ *schema.Object) (*Object, e
 		var args []FieldArgument
 		for _, arg := range field.Args {
 			newArg := FieldArgument{
-				GQLName: arg.Name.Name,
-				Type:    types.getType(arg.Type),
-				Object:  obj,
+				GQLName:   arg.Name.Name,
+				Type:      types.getType(arg.Type),
+				Object:    obj,
+				GoVarName: sanitizeGoName(arg.Name.Name),
 			}
 
 			if !newArg.Type.IsInput && !newArg.Type.IsScalar {